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Query: UNIPROT:P20366 (substance P)
21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The presence and the possible mechanism of action of the inhibitory nonadrenergic, noncholinergic nerve system (i-NANC) were investigated in guinea pig pulmonary artery (PA) precontracted with U44069 (a thromboxane analog). In the presence of alpha adrenergic blockage, electrical field stimulation induced a frequency-dependent, tetrodotoxin-sensitive relaxation. This relaxation was reduced by 9.1 +/- 1.9 and 19.4 +/- 2.8% by atropine (1 microM) and combined atropine and propranolol (both 1 microM), indicating that the main component is mediated by i-NANC neural mechanisms. In the branch PA rings, this i-NANC relaxation was unaffected by pretreatment with a cyclooxygenase inhibitor (indomethacin, 10 microM), 5-lipoxygenase inhibitor (A63162, 1 microM) or substance P desensitization, but was inhibited markedly by the P2y-purinoceptor antagonist reactive blue 2 (30 microM) and slightly potentiated by the peptidase alpha-chymotrypsin (2 U/ml). L-NG-monomethyl-arginine(L-NMMA), a nitric oxide synthesis inhibitor, caused a concentration-dependent inhibition of the i-NANC relaxation (53.9 +/- 4.1% at 100 microM), but had no effect on equivalent nitroprusside-induced relaxation. The inhibitory effect of L-NMMA was reversed completely by L-arginine (300 microM), but not by D-arginine (300 microM). Removal of vascular endothelium greatly reduced the i-NANC relaxation in the branch PA rings, but had no effect on i-NANC relaxation in main PA rings. Both in vivo capsaicinization and in vitro desensitization with capsaicin (1 microM) caused a significant reduction of the i-NANC relaxation in main PA, but had no significant effect in the branch PA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Endothelium-dependent nonadrenergic, noncholinergic neural relaxation in guinea pig pulmonary artery. 173 4

In addition to the classical transmitters noradrenaline and acetylcholine, other transmitters have been identified in perivascular nerves, including 5-hydroxytryptamine, ATP and a number of peptides. This paper discusses pre- and postjunctional neuromodulation of vascular transmission, and cotransmission involving noradrenaline, ATP and neuropeptide Y in sympathetic nerves, acetylcholine and vasoactive intestinal polypeptide in parasympathetic nerves, and substance P, calcitonin gene-related peptide and ATP in 'sensory-motor' nerves. Vasomotor nerves derived from intrinsic neurones, for example in the heart and gut, are also discussed. Subpopulations of endothelial cells store and release a variety of substances, including acetylcholine, substance P, ATP, 5-hydroxytryptamine, vasopressin and angiotensin II, that act on receptors on endothelial cells and lead to the production of endothelium-derived relaxing factor (identified as nitric oxide) which, in turn, produces vasodilation in response to changes in flow and hypoxia. Endothelium-derived contracting factors such as endothelin may also be released. There appears to be a resting dynamic balance between endothelium-derived vasodilator tone and sympathetic vasoconstrictor tone, which is altered under different physiological and pathophysiological circumstances. Long-term (trophic) interactions between perivascular nerves and endothelial cells are discussed, as are the changes in vascular control mechanisms that occur with ageing and hypertension and in the nerves that remain following trauma or surgery.
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PMID:Local mechanisms of blood flow control by perivascular nerves and endothelium. 198 71

1. Supernatants prepared from the rabbit brain, lung and liver caused an endothelium-dependent and volume-related contraction of the phenylephrine-pretreated rabbit aorta and inhibited relaxation due to acetylcholine (ACh). 2. Perfusion in situ of the rabbit lung or liver with Krebs solution substantially reduced or removed the endothelium-dependent inhibitor. Spectrophotometric analysis revealed the presence of substantial amounts of haemoglobin (1.8-2.1 microM) in these organ supernatants. 3. Supernatants prepared from the Krebs-perfused rabbit brain retained the ability to contract the phenylephrine-pretreated rabbit aorta and to inhibit relaxation due to ACh and substance P (SP). Rabbit brain supernatant did not reduce the vasodilator effect of sodium nitroprusside (NP) or nitric oxide (NO). 4. Rabbit brain supernatant contained low (less than 0.35 microM) concentrations of haemoglobin. 5. The inhibitory effect of rabbit brain supernatant was reversed by L-arginine (500 microM) but not D-arginine (500 microM). 6. The inhibitor of endothelium-dependent vasodilatation present in rabbit brain was not removed by dialysis (24 h, 4 degrees C) but was partially precipitated by ammonium sulphate (30% w/v). 7. Rabbit brain contains an endogenous inhibitor of vascular NO biosynthesis. The identity of this inhibitor is not known although it seems likely to be a large peptide or protein.
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PMID:Rabbit brain contains an endogenous inhibitor of endothelium-dependent relaxation. 208 9

The great discovery by Furchgott of the relaxing factor released from the endothelium (EDRF) awakened us to the necessity to reevaluate the functional importance of endothelial cells that have been chemically or physically stimulated. EDRF was first demonstrated to be released by acetylcholine, substance P, bradykinin and calcium ionophore A23187; thereafter, many substances have been found to release EDRF. This factor is quite unstable, is not produced by cyclooxygenase, and is an activator of soluble guanylate cyclase that synthesizes cyclic GMP; its action is suppressed by antioxidants via the superoxide anions produced, potentiated by superoxide dismutase and abolished by methylene blue and oxyhemoglobin. Recently, the role of lipoxygenase products in the production of EDRF was evaluated with new 5-lipoxygenase inhibitors without antioxidant activity. During the last couple of years, the actions and chemical properties of EDRF were verified to be quite similar to those of nitric oxide (NO); therefore, the hypothesis of "EDRF = NO" is widely being accepted. NO is produced from L-arginine via catalysis by an enzyme that is activated by Ca2+. The enzyme activity is inhibited by L-monomethyl arginine and other L-arginine analogs. Chemical and physical stimulations increase intracellular Ca2+ in endothelial cells that seems to be associated with K(+)-channel opening and hyperpolarization. Current interests are directed to the possible roles of NO in the regulation of nerve function. There are evidences suggesting that NO modulates adrenergic nerve function in blood vessels and some brain cell functions regulated by cellular cyclic GMP. Particularly, NO may be a transmitter substance in non-adrenergic, non-cholinergic vasodilator nerves innervating the cerebral arteries. Future investigations will determine the physiological roles of EDRF or NO and its relationships to pathophysiology of vascular dysfunctions, such as vasospasm and those related to hypertension, diabetes, aging, etc., and the extended roles of NO in nerve function, inflammation, immune reactions, etc. would be clarified more extensively by accelerated progress in this field of research.
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PMID:[Endothelium-derived relaxing factor (EDRF)]. 216 93

The response to small peptides such as Arg-vasopressin, oxytocin and tachykinins was investigated in cultured porcine aortic endothelial cells. The production of endothelium-derived nitric oxide was assessed indirectly by the accumulation of cyclic GMP, a response that is due to the increased activity of soluble guanylate cyclase of the endothelial cells after release of the mediator. Arg-vasopressin, oxytocin, substance P and physalae-min (an analog of substance P, pGlu-Ala-Asp-Pro-Asn-Lys-Phe-Tyr-Gly-Leu-Met-NH2) markedly and transiently stimulated the production of cyclic GMP without affecting that of cyclic AMP. Treatment of endothelial cells with either hemoglobin or methylene blue reduced significantly both the basal and stimulated level of cyclic GMP. The production of cyclic GMP evoked by Arg-vasopressin and substance P was inhibited selectively by NG-monomethyl-L-arginine but not by its D-enantiomer. The neurohypophyseal hormones and related peptides stimulated the accumulation of cyclic GMP in a concentration-dependent manner, with the following relative order of potency: oxytocin greater than Lys-vasopressin greater than Arg-vasopressin much greater than [deamino-Cys1, D-Arg8]-vasopressin. The production of cyclic GMP evoked by oxytocin was inhibited selectively by [d(CH2)5, Tyr(OMe)2, Orn8]-vasotocin, an oxytocin antagonist. The production of cyclic GMP evoked by Arg-vasopressin and Lys-vasopressin was inhibited by [beta-mercapto-beta, beta-cyclopentamethylene-propionyl1, O-Me-Tyr2, Arg8]-vasopressin, a selective V1-receptor antagonist. The moderate production of cyclic GMP evoked by [deamino-Cys1, D-Arg8]-vasopressin was inhibited significantly by the V1-receptor antagonist. The peptide antagonists affected only minimally or not at all the production of cyclic GMP evoked by a donor of nitric oxide, SIN-1 (3-Morpholino-Sydnonimine). These observations indicate that 1) neurohypophyseal hormones and tachykinins stimulate the accumulation of cyclic GMP in cultured porcine aortic endothelial cells by increasing the production of endothelial-derived nitric oxide, which in turn enhances the activity of soluble guanylate cyclase; 2) the production of cyclic GMP in response to oxytocin is due to activation of oxytocinergic receptors; and 3) the production of cyclic GMP evoked by Arg-vasopressin and Lys-vasopressin is due mostly to activation of V1-vasopressinergic receptors.
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PMID:Neurohypophyseal peptides and tachykinins stimulate the production of cyclic GMP in cultured porcine aortic endothelial cells. 217 9

The endothelium modulates coronary vascular tone by the release of endothelium-derived relaxing or contracting substances. The endothelium-derived relaxing factor has been identified as nitric oxide synthesized in endothelial cells from L-arginine. The endothelium can release other relaxing substances such as prostacyclin and a hyperpolarizing factor. Endothelin-1 is a potent vasoconstrictor peptide formed by endothelial cells, and is likely to be the physiologic antagonist of endothelium-derived relaxing factor. Other putative contracting factors include superoxide anions and products of arachidonic acid metabolism. Endothelium-derived relaxing factor is released spontaneously and in response to flow, platelet-derived products (that is, serotonin, thrombin and adenosine diphosphate) and certain autacoids (that is, acetylcholine, bradykinin, histamine, substance P, vasopressin, alpha-adrenergic agonists). A considerable heterogeneity of responses exists among vessels of different size from different anatomic origin and different species. Hypercholesterolemia, atherosclerosis, hypertension and myocardial ischemia or reperfusion, or both, impair endothelium-dependent relaxation. Under normal conditions, endothelium-derived relaxing factor appears to dominate the control of vascular tone of large and small coronary vessels, whereas in disease states, endothelium-derived contracting factors are released. Impairments of endothelial function may be important in the development of various forms of cardiovascular disease.
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PMID:Endothelial control of vascular tone in large and small coronary arteries. 240 18

1. Microradiographic techniques have been used to show that endothelium-derived relaxing factor (EDRF), which is believed to be nitric oxide, influences vasomotor responses in small arteries and arterioles down to 25 micron in diameter in an isolated, intact, buffer-perfused ear preparation of the rabbit. Arteries down to 75 micron in diameter, i.e. the central ear artery (G0) and its first three generations of branch vessels (G1, G2 and G3) were studied quantitatively. 2. Relative constrictor responses to 1 micron 5-hydroxytryptamine (5-HT) and the combination of 1 microM 5-HT and 1 microM histamine diminished progressively from G0 to G3. Constrictor responses to 5-HT were doubled in all generations by 1 microM haemoglobin which abolishes EDRF activity. 3. Relative dilator responses to acetylcholine or to substance P in preconstricted arteries were, in contrast, equal in the different generations. Mean -log (IC50) values calculated from diameter measurements were 7.63 +/- 0.10 M and 9.80 +/- 0.11 M, respectively. These dilator responses were abolished by 1 microM haemoglobin, implying that they were EDRF-mediated. Spatial homogeneity of relative dilator responses was found also with glyceryl trinitrate (10 or 50 microM) whose activity is thought to depend on biotransformation to nitric oxide, in both the presence and the absence of haemoglobin. 4. This finding of spatial homogeneity of the diameter response to changes in EDRF activity (or to glyceryl trinitrate) implies that EDRF influences hydrodynamic resistance more in vessels where constrictor tone is high.
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PMID:Endothelium-derived relaxing factor (EDRF) and resistance vessels in an intact vascular bed: a microangiographic study of the rabbit isolated ear. 245 43

Porcine or bovine endothelial cells cultured on microcarrier beads, packed into adapted chromatographic columns, perfused with Krebs' buffer and activated with appropriate stimuli (e.g. bradykinin, ADP or phospholipase C) release EDRF and prostacyclin into the perfusing fluid. In the effluent EDRF and prostacyclin might be bio-assayed using the Vane's superfusion cascade (rabbit aortic strips and bovine coronary artery strips, respectively) against nitroglycerine (GTN) and synthetic prostacyclin standards. Prostacyclin might be also quantified as 6-keto-PGF1 alpha by RIA. A spatial separation of the generator (endothelial cells) from the effector (vascular smooth muscle) has allowed to prove that EDRF is nitric oxide, that its activity is inhibited by superoxide anions and by chemicals which act via free radicals, finally, that the release of EDRF and prostacyclin is coupled by a receptor-mediated activation of phospholipase C. Although so successful, the above technique suffers from its essentials, i.e. from using cultured cells instead of fresh intact endothelial cells. Cultured endothelial cells are not responsive to many receptor agonists including acetylcholine, substance P and 5-hydroxytryptamine. Unlike fresh intact endothelial preparations the cultured cells which are perfused with Krebs' buffer generate superoxide anions at such concentrations that it might be obligatory infusing superoxide dismutase in order to detect EDRF. Nonetheless, a couple of data obtained with the cultured endothelial cells have been reproduced in the fresh cell preparations, e.g. release of EDRF by ADP and ATP, a coupled release of EDRF and prostacyclin by phospholipase C or a paradoxical augmentation of the sodium-nitroprusside-induced vasorelaxation by methylene blue.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Endothelium-derived relaxing factor (EDRF) from cultured and fresh endothelial cells. 247 Mar 61

1. The effects of the specific inhibitor of nitric oxide (NO) formation, NG-monomethyl-L-arginine (L-NMMA), on resting systemic arterial blood pressure (BP) and on the actions of both endothelium-dependent and endothelium-independent vasodilators were investigated in the anaesthetized, normotensive rat. 2. Intravenous administration of L-NMMA (12.5-50 mg kg-1; 47-188 mumol kg-1) but not its enantiomer, D-NMMA, induced a dose-related increase in BP, which was reversed by the intravenous administration of L-arginine (150-600 mumol kg-1), but not D-arginine. 3. The vasodepressor responses to intravenous administration of the endothelium-dependent vasodilators, acetylcholine, bradykinin and substance P were significantly inhibited by L-NMMA (94 and 188 mumol kg-1 i.v.), but not by D-NMMA. 4. The inhibition by L-NMMA of these vasodepressor responses was reversed by administration of L-arginine, but not D-arginine. 5. Endothelin (ET-1) induced dose-related vasodepressor responses following bolus intravenous administration, which were significantly inhibited by L-NMMA but not by D-NMMA. This inhibition was reversed by administration of L-arginine. 6. The vasodepressor effects of the endothelium-independent vasodilators, glyceryl trinitrate or prostacyclin, were not significantly inhibited by L-NMMA. 7. These findings with L-NMMA suggest that resting blood pressure in the rat is modulated by endogenous NO biosynthesis and that endothelium-dependent vasodilators act through the formation of endogenous NO to exert their actions in vivo.
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PMID:Modulation of the vasodepressor actions of acetylcholine, bradykinin, substance P and endothelin in the rat by a specific inhibitor of nitric oxide formation. 247 42

Endothelium-dependent relaxation of blood vessels is produced by a large number of agents (e.g., acetylcholine, ATP and ADP, substance P, bradykinin, histamine, thrombin, serotonin). With some agents, relaxation may be limited to certain species and/or blood vessels. Relaxation results from release of a very labile non-prostanoid endothelium-derived relaxing factor (EDRF) or factors. EDRF stimulates guanylate cyclase of the vascular smooth muscle, with the resulting increase in cyclic GMP activating relaxation. EDRF is rapidly inactivated by hemoglobin and superoxide. There is strong evidence that EDRF from many blood vessels and from cultured endothelial cells is nitric oxide (NO) and that its precursor is L-arginine. There is evidence for other relaxing factors, including an endothelium-derived hyperpolarizing factor in some vessels. Flow-induced shear stress also stimulates EDRF release. Endothelium-dependent relaxation occurs in resistance vessels as well as in larger arteries, and is generally more pronounced in arteries than veins. EDRF also inhibits platelet aggregation and adhesion to the blood vessel wall. Endothelium-derived contracting factors appear to be responsible for endothelium-dependent contractions produced by arachidonic acid and hypoxia in isolated systemic vessels and by certain agents and by rapid stretch in isolated cerebral vessels. In all such experiments, the endothelium-derived contracting factor appears to be some product or by-product of cyclooxygenase activity. Recently, endothelial cells in culture have been found to synthesize a peptide, endothelin, which is an extremely potent vasoconstrictor. The possible physiological roles and pathophysiological significance of endothelium-derived relaxing and contracting factors are briefly discussed.
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PMID:Endothelium-derived relaxing and contracting factors. 254 95


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